// ============================================================================
// pccontrol.go — 电源控制
//
// 关机 / 重启 / 休眠 / 锁屏命令（Windows 下用 shutdown 与 rundll32），
// 支持延迟执行与取消，并提供当前命令状态查询。
// ============================================================================
package main

import (
	"fmt"
	"net/http"
	"os/exec"
	"runtime"
	"strconv"
	"sync"
	"time"

	"github.com/gen2brain/beeep"
	"github.com/gin-gonic/gin"
)

// 电源命令默认延迟执行时间（Windows 下交给 shutdown /t 系统计时，服务崩溃倒计时仍有效）
const pcShutdownDelay = 30 * time.Second

// pcCommand 电源命令类型
type pcCommand string

const (
	pcPoweroff pcCommand = "poweroff" // 关机
	pcRestart  pcCommand = "restart"  // 重启
	pcSleep    pcCommand = "sleep"    // 休眠
	pcLock     pcCommand = "lock"     // 锁屏
)

// PCStatus 电源命令状态快照，供 API 与「主机」页查询
type PCStatus struct {
	Command       string `json:"command"`        // 最近一次命令类型
	Pending       bool   `json:"pending"`        // 是否有待执行命令
	ExecuteAt     string `json:"executeAt"`      // 计划执行时间
	RemainingSecs int    `json:"remainingSecs"`  // 剩余秒数
	ClientIP      string `json:"clientIp"`       // 最近一次请求的客户端 IP
	RequestTime   string `json:"requestTime"`    // 最近一次请求时间
	Requested     bool   `json:"requested"`      // 是否收到过请求
}

var (
	pcMu         sync.Mutex
	pcTimer      *time.Timer // 休眠 / 锁屏等不支持系统计时的命令用 Go 计时
	pcExecuteAt  time.Time
	pcPending    bool
	pcPendingCmd pcCommand
	pcSystemTimer bool // 是否已交给系统计时（shutdown /t）

	pcLastClientIP string
	pcLastTime     time.Time
	pcLastCmd      pcCommand
	pcRequested    bool
)

// pcSystemCommand 构造系统命令；返回 nil 表示该命令需 Go 计时后立即执行
func pcSystemCommand(cmd pcCommand, delaySec int) *exec.Cmd {
	switch runtime.GOOS {
	case "windows":
		switch cmd {
		case pcPoweroff:
			return exec.Command("shutdown", "/s", "/t", strconv.Itoa(delaySec), "/f")
		case pcRestart:
			return exec.Command("shutdown", "/r", "/t", strconv.Itoa(delaySec), "/f")
		}
	case "darwin":
		switch cmd {
		case pcPoweroff:
			return exec.Command("sudo", "shutdown", "-h", "+0")
		case pcRestart:
			return exec.Command("sudo", "shutdown", "-r", "+0")
		}
	case "linux":
		switch cmd {
		case pcPoweroff:
			return exec.Command("shutdown", "-h", "+0")
		case pcRestart:
			return exec.Command("shutdown", "-r", "+0")
		}
	}
	return nil
}

// pcExecuteNow 立即执行休眠 / 锁屏（这类命令无系统计时，直接执行）
func pcExecuteNow(cmd pcCommand) {
	var execCmd *exec.Cmd
	switch cmd {
	case pcSleep:
		switch runtime.GOOS {
		case "windows":
			execCmd = exec.Command("rundll32.exe", "powrprof.dll,SetSuspendState", "0,1,0")
		case "darwin":
			execCmd = exec.Command("pmset", "sleepnow")
		default:
			execCmd = exec.Command("systemctl", "suspend")
		}
	case pcLock:
		switch runtime.GOOS {
		case "windows":
			execCmd = exec.Command("rundll32.exe", "user32.dll,LockWorkStation")
		default:
			execCmd = nil
		}
	}
	if execCmd == nil {
		fmt.Fprintf(apiLogRing, "[SYS] 不支持的命令 %s (OS: %s)\n", cmd, runtime.GOOS)
		return
	}
	if output, err := execCmd.CombinedOutput(); err != nil {
		fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 执行失败: %v | %s\n", cmd, err, string(output))
	} else {
		fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 执行成功\n", cmd)
	}
}

// pcAbortShutdown 取消系统关机 / 重启倒计时
func pcAbortShutdown() {
	if runtime.GOOS == "windows" {
		if output, err := exec.Command("shutdown", "/a").CombinedOutput(); err != nil {
			fmt.Fprintf(apiLogRing, "[SYS] 取消关机失败: %v | %s\n", err, string(output))
		} else {
			fmt.Fprintln(apiLogRing, "[SYS] 系统关机已取消")
		}
	} else {
		_ = exec.Command("shutdown", "-c").Run()
	}
}

// getPCStatus 返回当前电源命令状态快照
func getPCStatus() PCStatus {
	pcMu.Lock()
	defer pcMu.Unlock()

	status := PCStatus{
		Command:   string(pcLastCmd),
		Pending:   pcPending,
		ClientIP:  pcLastClientIP,
		Requested: pcRequested,
	}
	if !pcLastTime.IsZero() {
		status.RequestTime = pcLastTime.Format("01-02 15:04:05")
	}
	if pcPending {
		status.ExecuteAt = pcExecuteAt.Format("01-02 15:04:05")
		remaining := int(time.Until(pcExecuteAt).Seconds())
		if remaining < 0 {
			remaining = 0
		}
		status.RemainingSecs = remaining
	}
	return status
}

// handleDelayedCommand 通用延迟命令处理：优先交给系统计时，不支持则用 Go 计时
func handleDelayedCommand(c *gin.Context, cmd pcCommand, delay time.Duration, title string) {
	clientIP := c.ClientIP()
	delaySec := int(delay.Seconds())

	pcMu.Lock()
	pcLastClientIP = clientIP
	pcLastTime = time.Now()
	pcLastCmd = cmd
	pcRequested = true

	if pcPending {
		remaining := time.Until(pcExecuteAt).Round(time.Second)
		pendingCmd := pcPendingCmd
		pcMu.Unlock()
		c.String(http.StatusOK, "命令 %s 已在待执行，剩余 %v\n", pendingCmd, remaining)
		return
	}

	pcPending = true
	pcPendingCmd = cmd
	pcExecuteAt = time.Now().Add(delay)

	sysCmd := pcSystemCommand(cmd, delaySec)
	if sysCmd != nil {
		pcSystemTimer = true
		pcMu.Unlock()

		// 系统计时：立即下发 shutdown /t N，由系统自己倒计时
		if output, err := sysCmd.CombinedOutput(); err != nil {
			pcMu.Lock()
			pcPending = false
			pcPendingCmd = ""
			pcExecuteAt = time.Time{}
			pcSystemTimer = false
			pcMu.Unlock()
			fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 下发失败: %v | %s\n", cmd, err, string(output))
			c.String(http.StatusInternalServerError, "命令执行失败: %v\n", err)
			return
		}
		fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 交由系统计时 | %ds | 客户端 %s\n", cmd, delaySec, clientIP)
	} else {
		// Go 计时：延迟到点后立即执行
		pcSystemTimer = false
		cmdToExec := cmd
		pcTimer = time.AfterFunc(delay, func() {
			pcMu.Lock()
			pcPending = false
			pcPendingCmd = ""
			pcMu.Unlock()
			pcExecuteNow(cmdToExec)
		})
		pcMu.Unlock()
		fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 使用 Go 计时 | %ds | 客户端 %s\n", cmd, delaySec, clientIP)
	}

	_ = beeep.Notify("⚠ "+title, fmt.Sprintf("来自: %s\n将在 %d 秒后执行\n时间: %s", clientIP, delaySec, time.Now().Format("15:04:05")), "")
	c.String(http.StatusOK, "OK: %s\n", title)
}

// handlePoweroff 处理关机请求：延迟 pcShutdownDelay 秒后关机
func handlePoweroff(c *gin.Context) {
	handleDelayedCommand(c, pcPoweroff, pcShutdownDelay, "收到关机请求")
}

// handleRestart 处理重启请求：延迟 pcShutdownDelay 秒后重启
func handleRestart(c *gin.Context) {
	handleDelayedCommand(c, pcRestart, pcShutdownDelay, "收到重启请求")
}

// handleSleep 处理休眠请求：延迟 pcShutdownDelay 秒后休眠
func handleSleep(c *gin.Context) {
	handleDelayedCommand(c, pcSleep, pcShutdownDelay, "收到休眠请求")
}

// handleLock 锁屏不需要倒计时，直接执行
func handleLock(c *gin.Context) {
	pcMu.Lock()
	pcLastClientIP = c.ClientIP()
	pcLastTime = time.Now()
	pcLastCmd = pcLock
	pcRequested = true
	pcMu.Unlock()
	go pcExecuteNow(pcLock)
	c.String(http.StatusOK, "OK: 已锁屏\n")
}

// handleCancel 取消待执行命令：系统计时调 shutdown /a，Go 计时停定时器
func handleCancel(c *gin.Context) {
	pcMu.Lock()
	if !pcPending {
		pcMu.Unlock()
		c.String(http.StatusOK, "无待执行命令\n")
		return
	}

	cancelled := pcPendingCmd
	wasSystemTimer := pcSystemTimer

	pcPending = false
	pcPendingCmd = ""
	pcExecuteAt = time.Time{}
	pcSystemTimer = false
	if pcTimer != nil {
		pcTimer.Stop()
		pcTimer = nil
	}
	pcMu.Unlock()

	if wasSystemTimer {
		pcAbortShutdown() // 系统计时的倒计时由 shutdown /a 取消
	}

	fmt.Fprintf(apiLogRing, "[SYS] 命令 %s 已取消 | 客户端 %s\n", cancelled, c.ClientIP())
	_ = beeep.Notify("✅ 命令已取消", fmt.Sprintf("%s 由 %s 取消", cancelled, c.ClientIP()), "")
	c.String(http.StatusOK, "命令已取消\n")
}

// handlePCStatus 返回当前命令状态（JSON）
func handlePCStatus(c *gin.Context) {
	c.JSON(http.StatusOK, getPCStatus())
}

// handleTimeSync 手动触发时间同步，返回具体结果
func handleTimeSync(c *gin.Context) {
	if err := syncSystemTime(); err != nil {
		c.String(http.StatusInternalServerError, "时间同步失败: %v\n", err)
		return
	}
	c.String(http.StatusOK, "时间同步成功\n")
}